Momordica charantia for type 2 diabetes mellitus.

Systematic review/meta-analysis of 4 randomized controlled trials in adults with type 2 diabetes mellitus, conducted in outpatient or clinic settings. Across the included trials, 479 participants were randomized to active Momordica charantia arms and comparisons included placebo, standard antidiabetic therapy, low-dose glibenclamide, or metformin.

Oral Momordica charantia (bitter melon) preparations were tested across four randomized trials, using capsules, tablets, or shade-dried whole-fruit preparations derived from fruit, seed, or leaf material. Doses varied widely across studies, including 6 capsules daily, 6 g/day, 500 mg/day, 1000 mg/day, and 2000 mg/day, with treatment durations ranging from 4 to 12 weeks; comparators included placebo, oral hypoglycaemic agents, low-dose glibenclamide, and metformin.

Overall, Momordica charantia did not show convincing improvement in glycemic control, and the review concluded that evidence is insufficient to support its use in type 2 diabetes. In the placebo-controlled trial by Dans 2007, there was no significant effect on HbA1c (MD 0.22, 95% CI -0.36 to 0.80), fasting blood glucose (MD 0.66, 95% CI -1.69 to 3.01), total cholesterol, or BMI. In John 2003, fasting blood glucose (MD -0.70, 95% CI -22.40 to 21.00), postprandial glucose (MD -27.20, 95% CI -65.33 to 10.93), and serum fructosamine (MD -14.80, 95% CI -53.19 to 23.59) were also not significantly different from placebo. One 12-week trial of leaf tablets reported reductions in fasting blood glucose and HbA1c comparable to low-dose glibenclamide, and in Fuangchan 2011 the 2000 mg/day arm improved fructosamine within arm, but the between-treatment comparison was not significant (P = 0.43).

The evidence base was small, with only 4 trials and short follow-up of 4 to 12 weeks. The review noted generally high risk of bias, inconsistent preparations and dosing, incomplete reporting in some studies, and limited raw data, which reduce confidence in any apparent benefit. Adverse event reporting was limited and the results may not generalize well across different Momordica charantia products or patient populations.